A Sonoma man is suspected of robbing an acquaintance at gunpoint and then trying to bring drugs into the county jail, Sonoma County sheriff's officials said Wednesday.

A woman told Sonoma police Tuesday that she was robbed by a friend who gave her a ride from the Sonoma Market Shopping Center, Sonoma Chief Bret Sackett said.

She told officers the man pulled a gun out from under the dashboard, pointed it at her and demanded money. She said she gave $1,200 to the robber, who threatened to kill her if she told anyone.

Officers found the man driving near Fifth Street West and Andrieux Street. They stopped him and found a loaded .22-caliber handgun and a large amount of cash in the car, Sackett said.

Joseph Kauth, 22, was arrested on suspicion of robbery, making threats, being an ex-felon with a gun, possessing a loaded gun in a car and violating his parole.

As he was being booked into the Sonoma County Jail, a correctional deputy found a bullet, methamphetamine and heroin in his clothes, Sackett said. Deputies added suspicion of bringing drugs into the jail and possessing drugs to his arrest.